Impractical plan?

The new energy policy calls for shutting down reactors more than 40-years-old, not building any new nuclear reactors and only restarting existing reactors if they pass standards issued by a new regulatory agency.

Japan's powerful business lobby is pushing for the restart of shuttered factors, fearing power shortages and soaring utility bills.

The chairman of the Keidanren, or Japan Business Federation, Hiromasa Yonekura, is one of many critics who argue the phasing out nuclear power is not practical.

"There is no way we can accept this. I cannot think this is technologically possible," he said.

The head of major utility Kansai Electric Power, Makoto Yagi, worries the government did not seek out enough feedback from the public.

"I am not sure whether substantial national discussions were held on this issue," he said.

Japan has been heavily dependent on oil from the Middle East and foreign imports since 2011's nuclear disaster.

In the months following the meltdown, all of Japan's working reactors were shut down for routine safety checks, but only two of them have been restarted since.

Moving toward renewable energy

Prime Minister Yoshihiko Noda's ruling Democratic Party of Japan (DPJ) has recommended the country make greater use of renewable energy, and take further energy saving measures.

It also said Japan should develop resources in nearby waters and look to cheaper procurement of liquefied natural gas and other fossil fuels.

This was a sentiment echoed by Greenpeace, who "cautiously welcomed" the new policy.

"The government and energy utilities must make every effort to rapidly phase out nuclear power and deploy renewable solutions to avoid future disasters," it said in a statement.

The environmental group said Japan should use its zero-nuclear goal as a starting point and make "increasingly bold strides towards the sustainable green economy that will secure Japan's future prosperity".

But the organisation has questioned Tokyo's decades-long timeline to phase out nuclear power since all but two reactors in the nation have already been switched off.